Abstract: A compact dual pass interferometer for a plane mirror interferometer configured to receive an input radiation beam from a light source. An optical component has a partially reflective surface arranged to reflect a first portion of the input radiation beam to follow a first optical path directed towards an output terminal and further arranged to transmit a second portion of the input radiation beam to follow a second optical path, directed towards a first location on a reflective target surface and back to the partially reflective surface, then to a second location on the reflective target surface and back to the partially reflective surface, whereupon the second optical path is directed through the partially reflective surface to be recombined with the first optical path to provide a recombined optical path configured to provide an output radiation beam. The output terminal configured to deliver the output radiation beam to a detector.

Abstract: The present disclosure relates to an apparatus for enhancing contrast sensitivity and resolution in a grating interferometer by machine learning, which can improve both image contrast sensitivity and spatial resolution in a grating interferometer by machine learning, the apparatus including: an image acquisition unit; a numerical phantom generation unit, a convolution layer generation unit to extract features from input data; an activation function application calculation unit that can apply a rectified linear activation function to an output value of the convolution calculation to perform smooth repetitive machine learning; a CNN repetitive machine learning unit that corrects a convolution calculation factor while repeatedly performing forward propagation and backward propagation processes; and an image matching output unit that matches and outputs features extracted by repetitive machine learning of the CNN repetitive machine learning unit.

Abstract: A distance measurement device and method based on secondary mixing of inter-mode self-interference signals of optical frequency combs are provided, which relate to the field of high precision laser distance measurement technologies. A dual-comb light source emits a dual-comb laser into a detection optical module to obtain the inter-mode self-interference signals carrying the to-be-measured distance information. The detection optical module outputs the inter-mode self-interference signals into a generation, acquisition and calculation module of inter-mode self-interference secondary mixing signals to generate the inter-mode self-interference secondary mixing signals, to thereby achieve signal acquisition and obtain a distance measurement result.

Abstract: An optical source is configured to simultaneously generate a set of four time-correlated photons comprising a first pair of photons and a second pair of photons. An interferometer is configured to receive a photon from the first pair of photons and configured to receive another photon from the first pair of photons. A first and a second detector configured to generate an electrical signal in response to measurements of an output of the interferometer. A third detector is configured to generate an electrical signal in response to measurement of a photon from the second pair of photons. A fourth detector is configured to generate an electrical signal in response to measurement of another photon from the second pair of photons.

Abstract: Totally six polarization-maintaining optical fibers having the same beat length are arranged at both ends of a single-mode optical fiber and both ends of a single-mode optical fiber coil, respectively. An angle between a principal axis of polarization in a first polarization-maintaining optical fiber and a plane of polarization of linearly polarized light from a light source is 45 degrees. The optical length of each of the six polarization-maintaining optical fibers is larger than a coherent length of the linearly polarized light from the light source. The total of the optical lengths of the six polarization-maintaining optical fibers into which polarization rotation in the process of passing through the single-mode optical fibers is factored is larger than the coherent length of the linearly polarized light from the light source.

Abstract: A bidirectional Littrow two-degree-of-freedom grating interference measurement device based on double gratings includes a transmission two-dimensional grating and a reflection two-dimensional grating. A dual-frequency laser emitted by a light source passes through the transmission two-dimensional grating with a specific grating pitch to form four beams in X direction and Y direction, the four beams are incident on the reflection two-dimensional grating at a Littrow angle, and the four beams diffracted by the reflection two-dimensional grating return to the transmission two-dimensional grating in an incidence direction along the same path; different orders of transmission light of the four beams of light in different directions may form stable interference signals carrying displacement information, and the stable interference signals are received by a detector.

Abstract: A method of evaluating performance of a flow cytometer configured to use a combination of two or more types of calibration particles having different morphologies from each other, includes a first classification step of classifying the calibration particles from each other based on a first optical characteristic by the flow cytometer which is an evaluation target, a second classification step of classifying the calibration particles from each other based on a second optical characteristic which is classifiable at a spatial resolution lower than a spatial resolution at which the first optical characteristic is classified, and the evaluation step of evaluating one or both of particle classification performance and a resolution of the flow cytometer based on a first classification result assessed in the first classification step and a second classification result assessed in the second classification step.

Abstract: A test fixture includes a base and an adjustable structure. The adjustable structure includes a limiting block, a locking block, and a fixing member. The limiting block is disposed on the base. The locking block is disposed on the base and abuts an edge of the limiting block to lock the limiting block in position. The fixing member is disposed on the limiting block to fix the limiting block on the base. When the locking block is moved from a first position to a second position, the locking block unlocks the limiting block, the fixing member is loosened, and the limiting block can rotate on the base. After the limiting block is rotated, the locking block is moved from the second position to the first position to lock the limiting block, and the fixing member is tightened to fix the limiting block on the base.

Abstract: A method for determining local position of an optical element associated with an optical path for transporting a laser beam in a working head of a machine for laser processing a material, includes generating a measurement beam of low coherence optical radiation traveling a measurement optical path, leading the measurement beam towards the optical element and the reflected or diffused measurement beam towards an optical interferometric sensor arrangement, generating a reference beam of low coherence optical radiation traveling a reference optical path and leading the reference beam towards the interferometric optical sensor arrangement, superimposing the measurement and reference beams on a common region of incidence, detecting a position of a pattern of interference fringes between the measurement and reference beams, and determining a difference in optical length between the measurement and reference optical paths as a function of the position of the interference pattern along an illumination axis, or of the

Abstract: A spherical multi-axis optical fiber sensing device is formed by a three-axis optical interference sensor composed of a multi-level opto-mechanical integrated unit kit. The opto-mechanical integrated unit kit is composed of three fiber rings, which are respectively a large fiber ring, a medium fiber ring and a small fiber ring. The multi-level opto-mechanical integrated unit kit is combined with the use of the mechanism component technology that can be freely rotated and positioned to achieve the functional purpose of establishing a three-axis orthogonal optical fiber sensing unit in a single sphere volume.

Abstract: The invention refers to a frequency shifter for heterodyne interferometry measurements, comprising a chip, an input waveguide configured to guide a light beam, at least four phase modulators, each being arranged to receive the light beam from the input waveguide and configured to modulate a phase of the light beam, an output combiner being arranged to let the light beams modulated by each phase modulator interfere, a first output waveguide coupled to the output combiner and configured to receive the modulated light beams constructively interfering at the output combiner, a second output waveguide coupled to the output combiner and configured to receive the modulated light beams destructively interfering at the output combiner, wherein the input waveguide, the phase modulators, the output combiner, the first output waveguide and the second output waveguide are arranged on the chip.

Abstract: A method of optical measurement for determining a spatial position of at least one luminous object in a sample includes: projecting onto the sample a dynamically optimized sequence of compact luminous distributions of different topological families; wherein the dynamically optimized sequence is determined based on data selected from the group consisting of a positioning hypothesis and a first set of measures; for each compact luminous distribution in the optimized sequence, generating an image of the at least one luminous object as illuminated thereby; and algorithmically analyzing the generated images to obtain spatial position information of the at least one luminous object.

Abstract: An optical measurement system measuring optical parameters of an object is provided. The object includes at least two light-transmitting layers. The optical measurement system includes a light source module, an image capture module, and a controller. The light source module emits at least two measurement light beams toward the object. The measurement light beams are respectively incident on the object at different angles. The image capture module receives light spots formed on a sensing surface of the image capture module by at least two first light beams after the measurement light beams are reflected by the object and at least two second light beams after the measurement light beams are refracted and reflected between the object. The controller is electrically connected to the image capture module to obtain positions of the light spots. The controller calculates the optical parameters of the object according to the positions of the light spots.

Abstract: A broadband interferometry for a measurement range extension beyond a coherence length of a light source is achieved through a local oscillation of the reference beam is replicated by a cavity multiplication or cascading optical delayed lines with a fiber optic cavity, and quantifiable optical properties including a wavelength group delay, a chromatic dispersion, a polarization mode dispersion and a model dispersion are inserted into the local oscillation of the reference beam to incrementally quantify the replicated copies of the local oscillation as the number of the delayed copies of the local oscillation increase for extension of a measurement rage to the target.

Abstract: This application discloses a measurement apparatus that does not use a femtosecond laser light source and a delay stage. The measurement apparatus mixes a first laser light from a first CW laser light source and a second laser light from a second CW laser light source to generate an interference light having a beat in a range from GHz to THz and demultiplexes the interference light into a pump light and a probe light. A generating photoconductive antenna is irradiated with the pump light, and a detecting photoconductive antenna is irradiated with the probe light. A current value of an electromagnetic wave propagating through a waveguide connecting the generating photoconductive antenna and the detecting photoconductive antenna is measured using a current system connected to the detecting photoconductive antenna.

Abstract: The invention refers to an optical device for heterodyne interferometry, comprising a chip, a beam splitter, a first waveguide arranged on the chip, light propagating in the first waveguide being guided to the beam splitter, a second waveguide arranged on the chip, light propagating in the second waveguide being guided to and/or from the beam splitter, wherein the beam splitter, the first waveguide, and the second waveguide form part of a Michelson interferometer, wherein the first waveguide and the second waveguide at least partially form two arms of the Michelson interferometer, and wherein two further arms of the Michelson interferometer are at least partially arranged outside the chip.

Abstract: Disclosed herein an apparatus and method for estimating a phase retarder and method of manufacturing the phase retarder using the same. The apparatus includes: a polarization element configured to output an incident light as a linear polarization and to make the linear polarization incident onto a phase retarder to be tested; a polarization image acquisition module equipped with a plurality of polarized pixels receiving an emitting light that is output from the phase retarder, on which the linear polarization is incident, and configured to obtain a polarization image based on the emitting light that is modulated in the polarized pixels; and a processor configured to evaluate quality of the phase retarder based on uniformity of a brightness value between polarized pixels of the polarization image. The polarized pixels modulate the emitting light based on a plurality of transmission angles and detects the modulated emitting light.

Abstract: A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and an oscillation circuit that outputs the reference signal to the demodulation circuit, and the vibrator is a signal source of the oscillation circuit.

Abstract: A method for scanning a scene is disclosed. According to the method, light is transmitted by a transmitter through a transmitter surface grating array, as a first elliptical pattern in a first lateral direction. Light is received by a receiver through a receiver surface grating array, from an area of a second elliptical pattern. The received light is reflected from the first elliptical pattern. The first elliptical pattern is orthogonal to the second elliptical pattern. The first elliptical pattern overlaps with the second elliptical pattern.

Abstract: A composite measurement system for measuring nanometer displacement is provided. The system includes: a light source, a polarization beam splitting prism, a first phase change module, a second phase change module, a first right-angle prism, a second right-angle prism, a non-polarization beam splitting prism, a scalar interference light collection module, a vector interference light collection module and a displacement calculation module. In the present disclosure, a photodetector is configured to collect an intensity of scalar interference light of the object to be measured being moved, to obtain a periodic light intensity change curve; a CCD camera is configured to collect images of interference vortex light of the object being moved; and the displacement calculation unit is configured to calculate a displacement of the object according to integer periods of the light intensity change curve and angles of image changes of the interference vortex light.